USB: usbip: vudc: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231103171428.3636570-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbip: Remove an unnecessary goto

When udc_dev = NULL, it is not necessary to goto out to return, just
return NULL directly. And the out goto label can be removed.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230805045631.1858638-1-ruanjinjie@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbip: Remove an unnecessary NULL value

The NULL initialization of the pointers assigned by kzalloc() first is
not necessary, because if the kzalloc() failed, the pointers will be
assigned NULL, otherwise it works as usual. so remove it.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20230804093253.91647-6-ruanjinjie@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc synchronize sysfs code paths

Fuzzing uncovered race condition between sysfs code paths in usbip
drivers. Device connect/disconnect code paths initiated through
sysfs interface are prone to races if disconnect happens during
connect and vice versa.

Use sysfs_lock to protect sysfs paths in vudc.

Cc: stable@vger.kernel.org
Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/caabcf3fc87bdae970509b5ff32d05bb7ce2fb15.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbip: convert platform driver to use dev_groups

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files. So take advantage of that
and do not register "by hand" any sysfs files.

Cc: Valentina Manea <valentina.manea.m@gmail.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190805193636.25560-5-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: Fix vep_free_request() null pointer checks on input args

Fix vep_free_request() to return when usb_ep and usb_request are null
instead of calling WARN_ON.

Signed-off-by: Shuah Khan <shuah@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: usbip: remove redundant pointer ep

Pointer ep is being assigned but is never used hence it is
redundant and can be removed.

Cleans up clang warning:
warning: variable 'ep' set but not used [-Wunused-but-set-variable]

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbip: Remove redundant license text

Now that the SPDX tag is in all USB files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Valentina Manea <valentina.manea.m@gmail.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: use monotonic timestamps

This gets rid of the deprecated do_gettimeofday() function in usbip.
The comment above vgadget_get_frame() mentions that it suffers
from issues with the time jumps due to suspend and settimeofday,
so I'm changing it to use ktime_get_ts64() to use monotonic times
that don't have this problem.

I couldn't tell whether we should use CLOCK_MONOTONIC or
CLOCK_MONOTONIC_RAW here, the difference being the exact rate
when correcting for NTP. I picked monotonic time since it doesn't
change the speed to the existing code and should be better
synchronized with other machines we talk to.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: fix off-by-one frame number calculation

vgadget_get_frame returns a frame number from 0 to 2046, which
may require an expensive division operation to wrap at one lower
than the usual number.

I can't see any reason for this, and all other drivers wrap at
a power-of-two number. My best explanation is that it was a simple
typo, so I'm changing the % modulo operator into a cheaper bitmask
that the other drivers use, to make it wrap after 0x7ff rather than
before it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: add SPDX identifiers to all remaining files in drivers/usb/

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/usb/ and include/linux/usb* files with the correct
SPDX license identifier based on the license text in the file itself.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc: Refactor init_vudc_hw() to be more obvious

Current implementation of init_vudc_hw() adds ep0 to ep_list
and then after looping through all endpoints removes it from
that list.

As this may be misleading let's refactor this function
and avoid adding and removing ep0 to eplist and place it
immediately in correct place.

In addition let's remove redundant 0 assignments as ep
array is zeroed during allocation.

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: ip: remove unnecessary & operation

Now that usb_endpoint_maxp() only returns the lowest
11 bits from wMaxPacketSize, we can remove the &
operation from this driver.

Cc: Valentina Manea <valentina.manea.m@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <linux-usb@vger.kernel.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

usb: usbip:checkpatch; fix bare use of unsigned

This patch fixes the following checkpatch warning for usbip files
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

Signed-off-by: Jai Krishna <rjk1024@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc: Fix apparent cut-n-paste error

Coverity picked up that this looks like a cut-n-paste from an almost
identical sequence below that didn't get its variable renamed.

Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: usbip: vudc: Rename find_endpoint() to vudc_find_endpoint()

As find_endpoint() is a global funcion rename it to vudc_find_endpoint()
to clearly mark where does it come from.

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: usbip: vudc: Fix WARN_ON() usage pattern

Fix WARN_ON() macro usage as suggested by Felipe.
Instead of using:
if (cond) {
WARN_ON(1);
do_stuff();
}

Use a better pattern with WARN_ON() placed in if condition:

if (WARN_ON(cond))
do_stuff();

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc: Add UDC specific ops

Add endpoints definitions and ops for both endpoints and gadget.
Add also a suitable platform driver and functions for handling
usbip events.

This commit is a result of cooperation between Samsung R&D Institute
Poland and Open Operating Systems Student Society at University
of Warsaw (O2S3@UW) consisting of:

Igor Kotrasinski <ikotrasinsk@gmail.com>
Karol Kosik <karo9@interia.eu>
Ewelina Kosmider <3w3lfin@gmail.com>
Dawid Lazarczyk <lazarczyk.dawid@gmail.com>
Piotr Szulc <ps347277@students.mimuw.edu.pl>

Tutor and project owner:
Krzysztof Opasiak <k.opasiak@samsung.com>

Signed-off-by: Igor Kotrasinski <i.kotrasinsk@samsung.com>
Signed-off-by: Karol Kosik <karo9@interia.eu>
[Various bug fixes, improvements and commit msg update]
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>